North China Electric Power University

Boe Technology Group Co., Ltd.

Beijing Boe Optoelectronics Technology Co., Ltd.

Jiahao Liu

Cheng Fang Wang

Tianshu Bi

Guoyi Xu

Xue Dong

Bo Gao

Ming Jin Chen

Yang Chen

Wenjia Sun

Jinxing Liu

Shaoru Zhang

Xiaozhou Liu

Yannan Xiong

A method implemented in a power grid including a DFIG wind turbine is provided. The method includes: assuming the DFIG wind turbine to be operated in a MPPT mode; generating a simplified transient model of the DFIG wind turbine, the simplified transient model including an equivalent circuit model, and an equivalent rotor motion model in a nonlinear form; linearizing the equivalent rotor motion model in the nonlinear form to be an equivalent rotor motion model in a linear form with respect to a steady-state operating point of the DFIG wind turbine; and determining a first contribution and a second contribution of the DFIG wind turbines to a post-disturbance frequency of the power grid, in a center of inertia (COI) frequency frame and in a frequency spatial variation frame, respectively, by incorporating the simplified transient model of the DFIG wind turbine into a frequency dynamics analysis.

System and method for stabilizing frequency of the power grid

Online estimation of area-level inertia can be used for frequency stability control in low-inertia power systems. This disclosure provides an area-level inertia online estimation method considering inter-area equivalent frequency dynamics. The disclosed method only needs one phasor measurement unit placed at any bus within each area. The inter-area equivalent frequency dynamics model for the multi-area power system is developed, which is employed to estimate area-level inertia under the small disturbance situation. Then, the area-level inertia estimation model boils down to a nonlinear parameter identification problem. The other boundary conditions of the disclosed method are derived by parameter identifiability.

Method and system for allocating optimal inertia in a power system

An exemplary two-step method for power system inertia online estimation is described. The first step is to accurately estimate the POI-level aggregated inertia. The second step is to calculate the system-level inertia constant by weighting all the POI-level aggregated inertia and to monitor the inertia spatial distribution. In one example embodiment, the PMU is installed at POI, the frequency spatial difference is considered, and the mechanical power is carefully treated.

Estimation system for aggregated inertia in a power system

Online estimation of area-level inertia considering inter-area equivalent frequency dynamics

Simplified transient model of DFIG wind turbine for power system frequency dynamics analysis

This disclosure provides a method to limit the post-disturbance node maximum RoCoF by optimizing UC decisions. The node initial RoCoF expressions under common disturbance types, including the load, the line switching, and the generator turbine disturbances, are derived. Then, the piecewise linear relationship between the node initial RoCoF and UC decision variables are obtained. To avoid numerical simulation of the node maximum RoCoF, two analytical constraints, i.e., the node initial RoCoF constraint and the COI maximum RoCoF constraint, are formulated in the UC model.

Method for avoiding blackouts caused by an RoCoF-based relay tripping in a power system

RoCoF constrained unit commitment considering spatial difference in frequency dynamics

Online estimation of POI-level aggregated inertia considering frequency spatial correlation

Disclosed are a driving method for a touch display panel, and a touch display apparatus. The driving method for a touch display panel includes: providing a sinusoidal signal y for each electrode block in a common electrode within a display period, wherein the display period includes N display stages, each display stage has M image frames, the refresh rate of the display period is greater than or equal to a refresh rate threshold value A, N&#x2265;2, M&#x2264;1, N is a positive integer, M is a positive number, and the refresh rate threshold value A is the maximum refresh rate that can be identified by human eyes; providing a data signal for multiple pixel electrodes; and an electric field, formed by the pixel electrodes and the common electrode, driving the inversion of liquid crystal molecules in a liquid crystal layer.

Driving method for touch display panel, and touch display apparatus

Growing community of inventors

Beijing, China

Jiahao Liu